The wings are also detached from the body, with a trailing spike at the elbow, suggesting a nonexistent rib/finger there. The overall design wouldn't work anyway; Disney's designers were probably relying on the parachute to make up for any airfoil problems, and in fact I doubt that dragon could have flown as built without a jet engine, not just a big fan.

In a cartoon, you can animate the smooth motions of a creature. In the video, that head was jerking around like a simple pneumatic system under medium pressure and the wings barely moved (if at all). Anyone caught up in "Wow, Disneyland!" was going to let it be a dragon, everyone else gets to see it for what it is. So in this case, it's all about imagination taking over where realistic design couldn't go.